Microgale dryas

Geographic Range

Tree shrew tenrecs, Microgale dryas , have only been found at the Ambatovaky Special Reserve in north-eastern Madagascar. Ambatovaky is a nature reserve located 50km west of the town Soanierana-Ivongo on the eastern coast of Madagascar.

• Biogeographic Regions
• ethiopian ethiopian
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

M. dryas lives only in the tropical rainforest of north-eastern Madagascar. This region includes dense vegetation (mainly evergreen forests). The area is characterized having sharp-peaked mountains and some aquatic elements because of the presence of two relatively large rivers. M. dryas is solely terrestrial and occupies this dense habitat.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest
• mountains mountains

Physical Description

Like other members of the genus Microgale , M. dryas is shrew-like in appearance. Its pelage is soft, short, and dense. It ranges in length from 170 to 180 mm, and weighs an average of 40 g. It is somewhat smaller than closely related species like M. dobsoni and M. gracilis . Microgale dryas can be distinguished from these species by its relatively short, grey tail and its distinctive pelage. The ventral pattern is generally reddish- or grey-brown. The dorsal pattern is unique because the guard hairs are long, with the mid-region of each hair flat and broad.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Reproductive and mating behavior of M. dryas is not well known. In other members of the genus, males and females may have stable relationships. Microgale dobsoni males and females associate with one another throught the year, and may be monogamous.

Although specific information about general reproductive behavior of M. dryas is unknown, the reproductive behaviors of other members of the genus Microgale are described below.

Reproduction generally begins with the onset of the rainy season in north-eastern Madagascar in September. Pregnancy lasts 2 to 3 months, and litters are generally born in November. There are generally between 1 and 4 offspring per litter. Females reproduce no more than twice in one year.

In M. talazaci , neonates weigh an average of 3.6 g. These young are weaned at about one month of age. Sexual maturity occurs at 21 months of age.

It is likely that M. dryas is like other members of the genus in these parameters.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

The specific parental investment and care patterns for M. dryas are not known. Information from related species in the same genus indicates that parental investment is similar to that of true shrews, Soricidae . Offspring are relatively helpless and remain in a nest guarded by the mother for about a month. Females of this genus care for the offspring, providing milk, grooming, and protection. The role of males in parental care has not been documented.

• Parental Investment
• no parental involvement
• altricial altricial
• female parental care female parental care
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female

Lifespan/Longevity

The lifespan of M. dryas is not known. Members of the family Tenrecidae generally live up to 6 years in the wild.

Behavior

Little is known about the behavior of M. dryas because it is rarely seen and is critically endangered. However, some behavioral traits have been observed of more common members of the genus Microgale , and these may be similar to those of M. dryas . These species tend to be terrestrial and insectivorous. They appear to be active at irregular intervals with foraging occurring during the day or at night. Some build nests for their young. They are generally solitary in the wild, and are aggressive toward unfamliar members of their species, but instances of pair-bonding have been documented in captive populations.

• Key Behaviors
• terricolous
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• solitary solitary

Home Range

The size of the home range of these animals is not known. However, other members of the genus are aggressive toward strangers, so it is likely that these animals are territorial.

Communication and Perception

Little is known about communication and perception of M. dryas , however other species of the genus Microgale have shown the following traits. They tend to have a well-developed sense of smell as well as tactile sense, especially through their whiskers (vibrissae). Some members of the genus produce a sound that may be used for communication, but sense of smell is likely the most important channel for communication. Agonism between unfamiliar individuals is a form of tactile communication. It is not known whether these animals use visual signals for communication.

• Communication Channels
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

M. dryas , like most other tenrecs, is primarily an insectivore. These animals consume a variety of invertebrates, including insects and arachnids. It is unknown whether M. dryas consumes plant materials or small vertebrates like its relatives in the family Tenrecidae .

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

Predation

Predators of M. dryas are likely larger sized mammals, reptiles, and birds. Evidence of M. dryas was found in pellets from a Madagascar red owl . It is possible that the nocturnal behavior of M. dryas is an anti-predator adaptation. No other adaptations to avoid predation are known in this species.

Ecosystem Roles

The role that M. dryas has in its ecosystem is unknown. It is not a common species, and has a very restricted range. Although it acts as predator for a variety of insects, it is not known how it impacts their populations. Similarly, although it may serve as prey to a number of other animals, it is not known whether it is an important prey item for these species, or how the availability of M. dryas as a food source affects these other animals.

Economic Importance for Humans: Positive

There are no known benefits that M. dryas has on humans. Because it is so rare, it is likely that it does not affect the ecosystem or humans greatly.

Economic Importance for Humans: Negative

There are no known adverse affects of M. dryas on humans.

Conservation Status

The IUCN lists M. dryas as the only critically endangered member of the Tenrecidae. It has only been found in the Ambatovaky Special Reserve and is extremely rare. The ongoing major threat to this population is habitat loss due to slash and burn agriculture and destruction of the rainforests. It is listed as critically endangered because it is only found at a single location and the number of these animals is thought to be declining.

Additional Links

Encyclopedia of Life

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Heather Gillespie (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Crowley, H. 2001. "Madagascar lowland forests (AT0117)" (On-line). World Wildlife Federation. Accessed April 16, 2004 at http://www.worldwildlife.org/wildworld/profiles/terrestrial/at/at0117_full.html .

Garbutt, N. 1999. Mammals of Madagascar . New Haven and London: Yale University Press.

Goodman, S., J. Benstead. 2004. The Natural History of Madagascar . Chicago and London: University of Chicago Press.

Grzimek, B. 2003. Tenrecs. Pp. 225-230 in Grzimek's Animal Life Encyclopedia: Mammals , Vol. 13, 2nd Edition. Farmington Hills: Gale Group.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition . Baltimore and London: The John Hopkins University Press.

Wilson, D., D. Reeder. 1993. Mammal Species of the World: A Taxonomic and Geographic Reference . Washington and London: Smithsonian Institution Press.

2003. "International Union for Conservation of Nature and Natural Resources" (On-line). Accessed April 15, 2004 at http://www.redlist.org/search/details.php?species=13356 .